The present invention relates to a container closure assembly and a method for opening a container closure assembly.
It is highly desirable to provide a container closure assembly which may be easily opened and reclosed without the use of a tool, especially with a tamper evident closure and also desirably incorporating a gas permeation barrier. It is particularly desirable to provide such a closure where it is necessary to maintain the integrity of the contents prior to opening, as for example, with carbonated beverages, and to enable re-closing the container with partially emptied contents. Thus, the closure should at least in part include a gas impermeable element or layer in order to maintain the integrity of the container contents prior to opening and it should also be capable of showing whether or not the container has been tampered with prior to opening.
It has been difficult to accomplish the foregoing with plastic closures, especially with closures which are convenient to use for a wide range of neck diameters including large diameters.
U.S. Pat. No. 5,325,976 to Valyi et al. shows a multilayered closure assembly with stepped portions, whereby twisting the closure member places the stepped portions under torsion and breaks a barrier layer at a weakened portion thereof and opens the container. U.S. Pat. No. 5,704,501 to Valyi also shows a multilayered closure assembly with a weakened, crystallized brittle portion in a barrier layer, whereby twisting a closure member breaks the barrier layer at the weakened portion and opens the container. U.S. Pat. No. 5,562,226 to Valyi et al. also shows a multilayered closure assembly where twisting of a closure member breaks a barrier layer at a weakened portion and opens the container.
It is an object of the present invention to provide a further improvement in the aforesaid container closure assemblies, barrier performance and which remains simple and convenient to operate.
It is a still further object of the present invention to provide an assembly as aforesaid which maintains the integrity of the contents prior to opening, which includes a tamper evident closure, and which enables re-closing of the container.
It is a further object of the present invention to provide an assembly as aforesaid which is easy to prepare, inexpensive and easy to use in practice.
Further objects and advantages of the present invention will appear hereinbelow.